I have added a tick box for the user to decide whether or not they want to apply a particular prompt. In case the user chooses both filters, I would like to OR them. The following is not working however.

If you can define not working a little better. I'm assuming there's no error message, but what is the outcome your getting vs what you expect to get. Also what type of data are you filtering? The pasted code is using both prompts on the same data item would be my first guess though.